*3.3. Influence of the LP on Material Microstructure*

LP is proved to be capable of modifying the surface roughness. However, it also affects the microstructure of the material and generates a recast layer that may modify the mechanical properties of the final part. To evaluate the influence of the LP on the microstructure, both LBM and LBM + LP surfaces have been cross-sectioned, polished, and etched using Kalling's 2 reagent. Notice that the polished surface shown in Figure 12b is the same LBM surface shown in Figure 12a that has been later subjected to LP. The thickness of the recast layer due to the polishing is of 22 μm, which is a circumstance to be considered depending on the final application of the part.

**Figure 12.** (**a**) Cross section of the LBM manufactured surface; (**b**) Cross section of the LBM + LP manufactured surface; (**c**) Detail of the recast layer generated on the surface due to polishing; (**d**) Internal microstructure developed as a result of the LMD process.

### *3.4. Final Test Part*

To demonstrate the potential of combining LMD, LBM and LP processes, a final test part is manufactured, Figure 13. First, starting from an Inconel 718 substrate, an oblique wall is built using MetcoClad 718 filler material with the same strategy and conditions used in the previous tests. Afterwards, the wavy surface resulting from the LMD is processed via LBM up to a 0.5 mm depth. Finally, the desired regions are laser polished.

**Figure 13.** Final shape of the manufactured final test part.
